1. Field of the Invention
This invention relates to texturization processes for proteinaceous materials.
2. Description of the Prior Art
Protein products are used in foods for their functionality as well as their nutritional value. The texture of a protein product contributes to its functionality as well as to its taste. Most vegetable protein products, e.g., soybean protein products, are in the form of powders or grits and a texturization technology has been developed to incorporate some textural characteristics to such soybean proteins. One known process produces meat substitutes from edible protein materials by forming fibers or filaments and then binding the fibers by suitable means. In this process protein fibers are prepared from a spinning dope of protein which is forced through a porous membrane such as a spinneret to form fibers. These fibers are coagulated in a bath containing suitable acids and salts and are oriented by suitable means, such as by a series of rolls revolving at increasing speeds. The fibers are placed in a salt solution, such as sodium chloride, of sufficient concentration to prevent the fibers from dissolving.
Textured protein foods can also be produced without spinning. Such a process involves rapid orientation and coagulation of protein material in a substantially undenatured, finely-divided, hydrated state under conditions which produce a shred-like structure. Orientation and coagulation of protein must be interrelated such that coagulation follows orientation of the molecules, whereby upon coagulation the oriented molecules are set in a shred-like condition. The process is conducted with about a 50% slurry of the protein material in water. The slurry is rapidly heated to and maintained at 360.degree. F. for about 1 minute in an autoclave and cooled rapidly. A shredded meat-like texture is obtained.
In various other processes mixtures of proteins can be used where one of the proteins serves as a binder. In such mixtures gluten or egg white is generally used as a heat-coagulating ingredient to set the extruded or shredded protein textures.
In another process a chewy gel is prepared by (a) adjusting the composition of a protein-water system, in particular the pH and the solids content, to a composition conducive to gel formation, (b) shaping of the system, and (c) applying heat as necessary to produce a chewy gel. The shaping may take place before or after either of the other steps of the process. The final products produced in accordance with this process simulate the fibrous texture, chewiness and structure of meats such as pot roast, roast beef, or the like.
In another process a textured soybean meal product is produced by moistening the soybean meal, mechanically working the moistened meal in an extruder at a temperature above 212.degree. F., pressurizing the moistened meal sufficiently to create a flowable substance, and extruding the pressurized substance through an orifice into a zone of lower pressure to produce a textured product.